package com.javadeobfuscator.deobfuscator.ui.component;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Insets;

import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;

/**
 * FlowLayout subclass that fully supports wrapping of components.
 */
public class WrapLayout extends FlowLayout
{
	private Dimension preferredLayoutSize;

	/**
	 * Constructs a new <code>WrapLayout</code> with a left alignment and a default 5-unit horizontal and vertical gap.
	 */
	public WrapLayout()
	{
		super();
	}

	/**
	 * Constructs a new <code>FlowLayout</code> with the specified alignment and a default 5-unit horizontal and vertical gap. The value of the alignment argument
	 * must be one of
	 * <code>WrapLayout</code>, <code>WrapLayout</code>,
	 * or <code>WrapLayout</code>.
	 *
	 * @param align the alignment value
	 */
	public WrapLayout(int align)
	{
		super(align);
	}

	/**
	 * Creates a new flow layout manager with the indicated alignment and the indicated horizontal and vertical gaps.
	 * <p>
	 * The value of the alignment argument must be one of
	 * <code>WrapLayout</code>, <code>WrapLayout</code>,
	 * or <code>WrapLayout</code>.
	 *
	 * @param align the alignment value
	 * @param hgap  the horizontal gap between components
	 * @param vgap  the vertical gap between components
	 */
	public WrapLayout(int align, int hgap, int vgap)
	{
		super(align, hgap, vgap);
	}

	/**
	 * Returns the preferred dimensions for this layout given the
	 * <i>visible</i> components in the specified target container.
	 *
	 * @param target the component which needs to be laid out
	 * @return the preferred dimensions to lay out the subcomponents of the specified container
	 */
	@Override
	public Dimension preferredLayoutSize(Container target)
	{
		return layoutSize(target, true);
	}

	/**
	 * Returns the minimum dimensions needed to layout the <i>visible</i> components contained in the specified target container.
	 *
	 * @param target the component which needs to be laid out
	 * @return the minimum dimensions to lay out the subcomponents of the specified container
	 */
	@Override
	public Dimension minimumLayoutSize(Container target)
	{
		Dimension minimum = layoutSize(target, false);
		minimum.width += (getHgap() * 2);
		return minimum;
	}

	/**
	 * Returns the minimum or preferred dimension needed to layout the target container.
	 *
	 * @param target    target to get layout size for
	 * @param preferred should preferred size be calculated
	 * @return the dimension to layout the target container
	 */
	private Dimension layoutSize(Container target, boolean preferred)
	{
		synchronized (target.getTreeLock())
		{
			//  Each row must fit with the width allocated to the containter.
			//  When the container width = 0, the preferred width of the container
			//  has not yet been calculated so lets ask for the maximum.

			Container container = target;

			while ((container == target || container.getSize().width == 0) && container.getParent() != null)
			{
				container = container.getParent();
			}

			int targetWidth = container.getSize().width;

			if (targetWidth == 0)
				targetWidth = Integer.MAX_VALUE;

			int hgap = getHgap();
			int vgap = getVgap();
			Insets insets = target.getInsets();
			int horizontalInsetsAndGap = insets.left + insets.right + (hgap * 2);
			int maxWidth = targetWidth - horizontalInsetsAndGap;

			//  Fit components into the allowed width

			Dimension dim = new Dimension(0, 0);
			int rowWidth = 0;
			int rowHeight = 0;

			int nmembers = target.getComponentCount();

			for (int i = 0; i < nmembers; i++)
			{
				Component m = target.getComponent(i);

				if (m.isVisible())
				{
					Dimension d = preferred ? m.getPreferredSize() : m.getMinimumSize();

					//  Can't add the component to current row. Start a new row.

					int compWidth = rowWidth + d.width + hgap * 2 + 2;
					if (compWidth > maxWidth)
					{
						addRow(dim, rowWidth, rowHeight);
						rowWidth = 0;
						rowHeight = 0;
					}

					//  Add a horizontal gap
					rowWidth += hgap;

					rowWidth += d.width;
					rowHeight = Math.max(rowHeight, d.height);
				}
			}

			addRow(dim, rowWidth, rowHeight);

			dim.width += Math.max(horizontalInsetsAndGap, maxWidth);
			dim.height += insets.top + insets.bottom + vgap * 2;

			//	When using a scroll pane or the DecoratedLookAndFeel we need to
			//  make sure the preferred size is less than the size of the
			//  target containter so shrinking the container size works
			//  correctly. Removing the horizontal gap is an easy way to do this.

			Container scrollPane = SwingUtilities.getAncestorOfClass(JScrollPane.class, target);

			if (scrollPane != null && target.isValid())
			{
				dim.width -= (hgap + 1);
			}

			return dim;
		}
	}

	/*
	 *  A new row has been completed. Use the dimensions of this row
	 *  to update the preferred size for the container.
	 *
	 *  @param dim update the width and height when appropriate
	 *  @param rowWidth the width of the row to add
	 *  @param rowHeight the height of the row to add
	 */
	private void addRow(Dimension dim, int rowWidth, int rowHeight)
	{
		dim.width = Math.max(dim.width, rowWidth);

		if (dim.height > 0)
		{
			dim.height += getVgap();
		}

		dim.height += rowHeight;
	}
}
